Four people were injured, including a child who was airlifted to hospital with life-threatening injuries, in a two-vehicle crash west of London Saturday morning.

A Jeep travelling south on Carriage Rd. collided with a minivan travelling west on Longwoods Rd. about 10:30 a.m., police said.

The Jeep was carrying a mother and her two sons, ages two and four, police said.

The two-year-old boy was airlifted to hospital with life-threatening injuries. The mother and four-year-old boy, along with the male driver of the minivan, were taken to hospital with non-life threatening injuries, police said.

The cause of the crash remains under investigation.

“What we do know at this point is Carriage Rd. southbound is controlled by a stop sign. At some point the Jeep proceeded through the stop sign, but it's still completely under investigation,” said Middlesex OPP Const. Laurie Houghton.

Both vehicles came to a rest at the edge of the intersection. The minivan had heavy damage to its front end.

Police closed Longwoods Rd. between Brigham and Martin roads, as well as Carriage Rd. between Sharon Dr. and Harris Rd. for several hours to investigate. The sections of road have been reopened.